Write with Positive Exponents $x ^ { - 3 / 7 }$

Multiple Choice

Write with positive exponents. Simplify if possible.
- $x ^ { - 3 / 7 }$

A) $\frac { 1 } { x ^ { 3 / 7 } }$
B) $\frac { 1 } { x ^ { 7 / 3 } }$
C) $\frac { - 1 } { x ^ { 3 / 7 } }$
D) $- x ^ { 3 / 7 }$